Superficially, anxiety and depression would seem to represent discrete psychiatric categories. That is, contrary to depression, if you're besieged by an anxiety attack, it feels as though your life is in peril--you're in a state of extreme agitation, your palms are sweating, your heart is pounding, and your breathing is labored. On the other hand, when you recall the worst depression you've ever suffered, what probably comes to mind is the terrible sadness, the sense of hopelessness, the feelings of worthlessness or guilt, and the almost total absence of appetite, libido, or interest in anything that surrounds you.

What this extended five-part post will demonstrate, however, is that there are far more links between these two distressful emotions and moods than typically realized. And some researchers in the field, increasingly aware of their fundamental similarities, have even conjectured that anxiety and depression may both be facets of yet another disorder, as yet not clearly identified (see Part 4 for a fuller discussion of this).

In this introductory part, I'd like to outline the broad distinctions between the syndromes of anxiety and depression, whereas in Part 2 my focus will be on illuminating how these two negative emotions warrant being viewed as complementary or overlapping--and in many ways almost indistinguishable. It may also be instructive to note here that in DSM-IV (the mental health professional's diagnostic bible), there's actually an appendix summarizing proposals for new categories of mental disorders that includes--"for further study"--the mood disturbance: "Mixed Anxiety-Depressive Disorder."

But in order to better appreciate the particular symptoms of anxiety and depression, which seemingly differentiate them from each other, let's first look at their most characteristic features.

The Ordeal of Anxiety

What defines individuals as anxious is that they feel threatened by people and circumstances that most people would take in stride. Experiencing fear--or even panic--with (objectively, at least) very little provocation, they live lives of chronic worry, insecurity, and a truly frightening sense of vulnerability. Tense, nervous, and hypervigilant (whether about a specific situation or just in general), it's difficult for them to relax or "let go."

Since strong emotions affect our body quite as much as our mind (which triggers them in the first place), the physical symptoms of anxiety can be every bit as disturbing as the emotion itself. Ultimately, your level of anxiety determines the severity of your symptoms. But if you've ever had a powerful anxiety (or worse, panic) attack, you've probably experienced increased muscle tension and rigidity, an accelerated heart rate or palpitations, light-headedness, chest pain, shortness of breath, a dry mouth, trembling, sweating and clammy hands, a queasy stomach, nausea, and perhaps even diarrhea. Behaviorally, your anxiety would have manifested itself through a pronounced restlessness, likely characterized by squirming and fidgeting; and you might have felt compelled to pace the floor, stamp your feet, clench your hands, grind your teeth, or some other kind of edgy, jittery, "wired" action.

Moreover, your feelings of apprehension or distress might have included a sense of being critically watched (and so making a terrible fool of yourself), a surreal perception of self-detachment or unreality (technically referred to as "depersonalization" or "derealization"), a fear of dying or impending doom, or (since you're feeling so out of control) even a sense of going crazy. Along with these most disconcerting feelings, you may experience yourself as uptight, dissociated, "flipped out," uncomfortably "energized" (because of the adrenalin surge accompanying your anxiety), or--at worst--absolutely terrified. And these many unnerving symptoms represent only a partial listing. For--as I'll illustrate in Part 2--many additional descriptors of anxiety are indicators of depression as well.

Common synonyms for depression include hopelessness, misery, melancholy, and despair. Although the term is now used loosely to describe anything from a blue mood to temporary feelings of lethargy or burn-out, properly defined it depicts a serious state of despondency.

Depressed individuals frequently report feelings of emptiness--of profound sadness or gloom. And whereas anxiety, with its many physiologically arousing features, revs up your engine, depression typically slows it down. So much so that if you're acutely depressed, not only can you experience a debilitating fatigue but both your speech and physical movement may be retarded--as though you simply can't get out of first gear.

Additionally, depression is characterized by pronounced apathy, or a loss of life satisfaction and (more specifically) a loss of interest in activities and pursuits enjoyed previously. A deep sense of pessimism, guilt, and worthlessness--at times to the point of contemplating (or even attempting) suicide--is also characteristic. Many so-called "vegetative" symptoms also lead to the diagnosis of depression--or, to employ the proper clinical nomenclature, Major Depressive Disorder. These symptoms include insomnia and early morning awakenings; decreased appetite and weight loss (or, though much less frequently, abnormal weight gain); loss of sexual drive; crying jags; and various aches, pains, and digestive difficulties.

Finally, as in my descriptions of anxiety, many of the features I've delineated as typical of depression occur not only in major depression but, to varying degrees, also in bipolar disorder, cyclothymia, and dysthymia (the last a milder, but more common--and chronic--form of depression).

Note 1: Part 2 will discuss the many crucial similarities and overlaps between anxiety and depression, which make them so complementary. Part 3--perhaps the most originative of this 4-part post--will go into the negative beliefs about yourself and the world around you that give rise to both these distressful mental/emotional states. Part 4 will look at the research findings and theoretical speculations on co-occurring anxiety and depression; and, finally, Part 5 will consider the various treatment considerations in devising the best therapy for helping those with both disorders.